Sifting apparatus.



SEARCH ROOM Patented Nov. 23, 1915. I

2 SHEETS-SHEET I:

w. LINDSAY.

SIFTING APPARATUS. APPucATioN min D,C.26|- 1914.

Patented Nov. 23, 1915,

2 SHEETS-SHEET 2.

' phates, gypsum; pigments, flour or" analogous substances or materials.

' UNITED strArEs PATENT OFFICE. i i 4 h men, orcmcaeo, ILLINOIS. I

SIFTING APPARATUS.

1 161,234. Specification o1 Letters Patent. Patented Nov, 23, 1915 i Application filed nec mberae, 1914. Serial 1%. 878,139.

To all whom it may concern: formed, is a reticulated screen 4, Fi 2 B it known that I, WILLIAM LINbsAY, a and 3, of woven wire, bolting cloth or other citizen of the United States, residin at suitable matenal, having a mesh of a prede- Chicago, in the county of Cook and tate term ned gage adapted to sift materials of of IlllIlOlS, have invented a new, useful, varylng: degrees of fineness, such, for exam and Improved SiftingApparatus, of which ple, as sand, enaineh-ng powder, Portland {the following is a description, reference cement orthe like. The gage of the screen being bad to the accompanying drawings, meshes may range from four or less, to forming a part of this specification, 'in three hundred to the inch, ac'cordin to the which corresponding numerals of reference character of the material. to betreate Bars in the different figures indicate like parts. {5, 5, are placed above and rigidly attached The object of my invention, generally 1n any approved way to the bars 1, with the v stated, is to fprovide a simple, efi'ective and screen 4, preferably inter osed between t a I improved si ing apparatus for sifting or them so as to aid in securing the latter, screening commmuted material, such, for while forming guards to prevent the mateexample, as sand, Portland cement, iron r al upon the screen from falling off at the particles, enameling powder, lime, phossldes. e frame membersmay be made -mater1al, such, for 3ample, as metal or ,wood,,but I prefer to use le uniform separation may ordinarily steel, in view of its greater resiliency. I a be accom 'lished with the use of small prefer to support the frame at the upper 7 screens an the operating appliances heretoand lower ends and would recommend that- I I fore employed in connection therewith, new the supports be made yielding or resilient,

. difficulties and complications at once arise, in order to prevent undue noise and jar to so especially in the treatment of'the finer masurrounding objects, although in other reterials, if uniformity of result, coupled with spects, rigid supports may answer equally vrelatively high speed, large capacity and .'well.. In the example illustrated in Fig. 1

economy of'construction, maintenance and the frame, is shown as bemg'suspended'by operation are to become controllin factors. 1 means of coiled springs 6, from fixed points, Without intending to limit mysel thereto, not shown, said frame being inclined at a it is to these latter considerations that my predetermined angle to the horizon to perinvention is more especially directed. I acmit the,coarser material topass over. A co'mplish said object in the manner hereinhopper 7, is located at the upper end for de.

after moreparticularly described and defi: hvermg upon the screen the material to be nitely' pointed out in'the claims. sifted. In the example illustrated in Figs.

In the drawings, Figure 1, is a side view 1 and 2, I have shown brackets orbridges in elevation, "portions thereof being shown 8, attached by means of bolts 9, to the under diagrammatically, of a sifting device emfaces of the bars 1. Rigidly secured to the bodying the features of my 'inventiom'Fig. brackets 8, are electro-magnets 10, the poles 2,-is an enlarged fragmentary section, taken of which are in operative proximity to the upon the line 2, Fig. 1, viewed in the direc bars 1, which, being of magnetic material, tion of the arrow, there shown,- Fig. 3, is a serveas armatures therefor. It should he plan view, Fig. 4, is a side elevation shownoted however, that in order to prevent ing a modified form, Fig. 5, is a central noise and wear, the magnets and armatures'loo section of a pulsator or'current-intetrupter, should not be permitted to make actual con- Fig. 6, is a side View of'a modified contact. An electric current generator 11, is struction, Fig. 7, is a plan view thereof, connected by means of leads 12, and 13,

and Fig. 8, is a plan view of a still further and 14, and 15, respectively, to the magnets modification.

Referring to the drawings, 1, Figs. 1 and frame-members. .The generator may be of 2, indicates rectilinear members or side-bars thecontinuous or alternating type. V which are arranged parallel to each other It is well known that a bar of metal or and are rigidly connected at the ends by wood is subject to vibration throughout its means of cross-bars 2 and 3, Fig. 3, so as lengt in wave form like thestrmg of a '110 to form a rectangular frame, Stretched musical instrument; the rate and amplitude from the upper surface of the frame thus of the vibrations being proportionete to the upon the upper and lower portions of the in a greatly exaggerated degree, the nodes bration. In the example illustrated in Fig.

1, the dotted line 16, is intended to indicate,

or wave-lines-which would occur when setting the bar 1 into vibration. Assuming the illustration to indicate the correct wavelength,- it will be seen that the ends of the bridges S, shouldbe placed substantially at or near the neutral points of the nodes as represented in the drawing.

The operation is as follows: Upon applying the electric current so as to alternately energize and deenergize the magnets 10, in rapid succession, the bar 1, is set in vibration by being first drawn toward the magnet and then released, thereby imparting a like vibratory movement to'thescreen.

The rate of vibration should be proportionate to the character of the material to be sifted; and inasmuch as the vibratory am.- plitude is modified by the rate, a low rate giving a large, and a high one a relatively small amplitude, it follows that for coarse material, such as very coarse sand, a low rate of, say, thirty-five vibrations per second, may be employed, while for fine material a rate of three hundred or more per second may be found desirable.

While a given arbitrary rate maybe impressed upon a bar by the sheer force of the stress applied, I recommend that the current frequency be made to conform as nearly as possible to thenormal vibratory rate which the bar itself would assume if set into vibration by a blow. This may be accomplished by first ascertaining the vibratory rate of the bar as determined'fiit'slefigth'find cross-sectional area, arrdlherr attuning the frequency of the cgrgent generator-moat; care. Berrfitalfe'fi'to empldywiie requisite number of magnets and to position'them in conformity to the number and length of the vibratory waves. A preferable way, however, and one which I recommend, in order to secure the best results, is to utilize the normal vibration of the bar itself to automatically govern the current freouency. In Fig. 4, I have shown one means by which this result may be accomplished, but I do not wish to be limited thereto, inasmuch as it may be varied without departing from the principle. involved. In the figure referred to, 1, indicates the frame-bar to be vibrated, which is the same as those shown in the previous figures, and being connected in like manner with the screen, is 'ven a corresponding reference numeraL- iitigidly attached to the upper end of said bar and arranged at right angles thereto, is a depending arm 17, having a bore 18, therein for the reception of a stationary supporting member, not shown. A fitting 19, is also rigidly attached to the lower end and is pro vided with a. bore 20, for the reception ofa like supporting member. Rigidly attached to the lower end of the arm 17, is an electromagnet 21, the poles of which are in operative proximity to, but separated from a rigid or stationary armature 22. One term inal of said magnet is connected by means of a lead 23, with an electro-generator- 24,

which, in turn, is connected by means ofa lead 25, with a metal boss 26, secured to a diaphragm in the manner hereinafter de-- scribed, of a current interrupter or pulsetor, generally designated -by 27. .Said interrupter is rigidly attached by means of a screw 28, to the arm 17, which is in elec trical connection with the other terminal of the magnet. The current, therefore, would pass from the coil of the magnet, through "the'lead 23,- generator 24:, lead 25, and interrupter 26, from whence it would be short circuit-ed through the arm 17, to the-opposite magnetic terminal. The construction of the interrupter is shown in Fig. 5,- in which 29, indicates a cup-shaped .metallic casing having a boss 30, into which the screw 28,

is threaded to secure it to thear'm 17. Said casing is provided with an annular shoulder 31, against which is fitted a flexible diaphragm 32, held in place by means of a ring 33. Attached to the inner face of the casing. by means of a screw 34:, is a carbon disk 35, while a like disk 36, is attached to the inner face of the diaphragm by means of a screw 37, which is passed through the dia phragn'i and tapped into the boss 26, to

which the lead 25, is secured. The disks 35, and 36, are separated from each other and the space between them, as well as that between the diaphragm and the walls of the casing, is filled with a loose body 38, of carbon particles or granules. It will thus be seen that when the electric circuit is closed with the generator, the current will pass through the circuit as generally described, and in doing so,'the passage will be through the boss 26, screw 37, carbon 36, carbon fi1l ing 38, carbon-disk 35, and casing 29, to the bar 17 and thence to the magnet. The energizing of the latter causes the lower end of the arm 17 to be pulled toward the rigid stationary armature 22. The arm 17,-acts as a lever with the support at 18, as a ful rcrum, by which thebar 1, is caused to bend with the first impulse of the current. As

soon, however, as a given tension is devel oped in the bar 1,-its resiliency causes it to recoil and a vibratory action is induced therein which reacts upon the diaphragm, causing the latter to vibrate as a result of the corresponding movement of the arm 17,

as the electric circuit is closed;-the rate of vlbr'ation being determined by the bar itself, the length and cross-sectional area which constitutes determining factors.

In Figs. 6 and 7, Ihave shown a. modification in which the bridges are placed above the frame bars 39, and 40, respectively, which bars are attached in any approved manner to underbars'41,-with the screen 4,

interposed between them, as in Fig. 2 The bars 41, are'attachedat their upper and lower ends.respectively to stationary sup-v ports 42, and 43.. In the example illustrated, the bridges 44, and 45, upon the bars 39,

words, are placed at different intervals upon said bars so as to modify "the character of the vibrations of the two bars by reversing the relative directions of movethe lines 48, in Fig. 7 This motion would ment and thus modifying the effect upon the screen to cause lateral as Well as up-an-d-.

down waves, the former being indicated by tend tocause the materialto be vibrated laterally as well as up and down and would tend toward greater rapidity in sifting. In the example under discussion, it is assumed that the bars 39, and40, may be made'of wood, in which case armatures 49, are rigidly attached to their upper faces to be acted upon by the magnets 10. p

In Fig. 8, a still further modification is indicated, in which the magnets 10, are placed at the sides of the bars 50, so as to induce a lateral vibration thereof. In this construction, it is essential that the crosswires'of the screen 51, should be sufficiently slack to permit of an appreciable lateral movement'of the" bars when the magnets are energized, which action would cause an alternate stretching and loosening of the cross-strands; thereby tending to toss the material upwardly upon the screen. In

such a case it is not necessary that the sidecal planes of the sides.

I do not wish to be limited to the con structionv 7 shown, inasmuch as it may be greatly varied.' For example, it is immaterial how the magnets are sup orted in their relation to the frame, whe or on or off,

.bars should be straight, except in the verti- "magnet in operative proximity thereto, a

member.

part vibration to the entire frame. It is also apparent that the screen need not be inclined. I

What I claim as my invention and desire to secure by Letters Patent is:

LA sifting apparatus, comprising, in combination, a frame having members adapted to be set in vibration by the direct influence of an electro-m ignet, a screen sup I ported by said frme operative proximity to said frame and a source of electricity in circuit with said electro-magnet, the current frequency of an electro-magnet in which is attuned to the normal rate of. vibration of said frame to cause synchronism between thetwo. .2. Asiftmg' apparatus, comprising, in combination, a screen, a frame adapted to V be set in vibration by the direct influence are staggered with respect to like bridges I 46, and 47,upon the bar 40; or'in other of an electrow-magnet, the constituent mem ers of said frame having a predetermined vibratory rate per unit of time, an electrosource' of electricity in circuit with said magnet and means, controlled by the"vi-" brat'ion of said frame for causing the rate of current pulsation to conform to the vi bratory rateof Said frame.

3. A sifting apparatus, comprising, in

combination, a frame having rectilinear screensupporting members, said member having a predetermined normal rate of vibration per unit of time,;a'screen supported thereby, a plurality ofelectro-magnets in operative, proximity to said screen-supportmg members, means for maintaining said magnets in fixed relation thereto, the disposition of said magnets conforming substantially to the normal vibratory wavelengths of said members, a source of electricity and means for causing an intermittent current in conformity to the normal vibratory rate of said frame members.

4. In a sifting apparatus, the combination of a screen, a vibratory frame-member adapted to be actuated by direct magnetic influence, said member having a predetermined normal rate of vibration per unit of time, an electro-magnet, a source of'electricity in circuit therewith and a pulsatory element interposed in said circuit, the same being actuated to cause an electric current pulsation with each wave vibration of the frame member whereby the rate of pulsation in the magnet may be caused to conform to'the vibratory rate of'said frame 5. A sifting apparatus in which is combined a frame-bar, adapted to be directly influenced by an electro-magnet, said bar having a given vibratory rate'per second, a

screen connected therewith, and electromagnet in operative proximity to said bar, a'

a. current interrupter in position to have its interruptions directly controlled by the vibratory action of said frame-member.

7. A sifting apparatus comprising a screen, a supporting frame therefor, said frame being adapted to be set in vibration when lines of stress are applied thereto at an angle to its axis by electro-magnetic action, an armature, an electro-magnet, one of which is adapted to vibrate with the frame while the other is stationary, a source of electricity and means-for causing a pulsatory intermission of the current, the rate of pulsation being in harmony with the normal yibratory rate of the frame to maintain synchronisr'n between the two.

8. A sifting apparatus, comprising a screen, a frame having a member adapted to be set into vibration when lines of stress are rapidly applied thereto at an angle to its axis, a bridge-member rigidly attached to said frame-member at predetern'lined points, an electro-magnet interposed between said bridge and frame-member and a source of electricity in circuit with said mag net, whereby said" bridge may serve to resist the pull of said magnet to cause said frame-member to yield to said pull and induce a vibration inv said frame-member in-v dependently of its supports.

9. A sifting apparatus, comprising, in combination, a screen, screen-supporting rnembers upon opposite sides thereof, electro-magnets arranged in fixed relation to said members for producing wave-vibrations therein, the magnets associated with v one member being alternated or staggered in position with respect to the relative positions of those upon the other to reverse the relative wave-actions, a source of electricity in circuit with said magnets and means for causing the current to pulsate or intermit, whereby a sinuous Wave-motion may be imparted to the screen in lateral curves. 7

WILLIAM LINDSAY. lVitnesses:

DAVID H. FLETCHER, LnsLm W. FRICKE 

